Question about GMC Denali

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1999 GMC Denali heater blower motor is always on high. The only way to stop it, while the vehicle is running, is to pull the 25A fuse. The switch does nothing, even in the "off" position.

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Hi,Sounds like your resister for your blower motor is shorted. this is mounted under the passenger side of the heater box where the blower motor is. This resister board has a reley mounted on it for high speed operation. very easy to change around 40 bucks at auto zone.

Posted on Aug 25, 2010

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